Typically a ball bearing, needle bearing or other types of bearings are mounted onto a shaft and also another object in order to permit rotation of the shaft relative to the object. Typically, the inner race of a bearing is pressed onto a shaft and the outer race of the bearing is pressed into a bearing seat defined within a housing. Due to longitudinal or axial thermal expansions and contractions of the shaft and/or the housing into which the bearing is seated, there must be made allowance for axial movement of the bearing relative to the shaft and/or relative to the housing. In order to provide for this longitudinal or axial movement, the bearing mounting must be loose enough to accommodate longitudinal or axial movement of the bearing. Upon rotation and loading of the bearing, the outer bearing and/or the inner bearing race may rotationally creep. For example the inner bearing race may creep (move) rotational on the outer diameter of the shaft causing abrasion, wear, distortion and/or fretting corrosion along the bearing seat contact surface.
This rotational creep is undesirable due to the damage that it can impart upon either the bearing, the housing that the bearing is mounted into and/or the shaft that the bearing is mounted onto.
The damage imparted by the rotational creep may become so extensive, that repair must be initiated which often can be expensive and require additional machining of housings and/or shafts and replacement of bearings which creates down time of the machine and therefore lost production to the manufacturing operation.